In most households, the bathroom lavatory is used for rinsing or cleaning numerous items, and frequently for cleaning small items such as small pieces of jewelry, removable teeth, and contact lenses, to name only a few. The problem encountered in such washing is the hazard of dropping a small item. Since such small items are frequently rinsed generously with the drain open, there is an imminent danger of losing the item down the drain. While some heavier items may lodge in the trap and be retrievable (through with some difficulty), other items might well pass entirely through the trap so that they are, for practical purposes, irretrievable. This is especially true of such items as contact lenses which are made of plastic and are light enough to be carried through traps and the like by even a small current of water.
One possible solution to the above stated problem is simply to close the drain of the lavatory. Such a solution is not really acceptable since the lavatory will fill with water after a certain amount of rinsing; furthermore, if the basin is filled with water a contact lens would be difficult to find because of the small differences in the refractive indexes of the lenses and the water. Another possible solution is the use of a strainer over the drain sufficiently fine to prevent passage of items dropped into the lavatory. While such a solution will be acceptable for special purpose lavatories and basins, it would not be acceptable in a conventional household lavatory that is used for diverse purposes. Additionally, the removal of the conventional drain plug and the installation of a fine strainer would be excessively expensive as a means to solve an infrequently recurring problem.